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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presence and activity of alkaline phosphatase in SAOS-2 and TE-85 human osteosarcoma cells grown in culture were examined at the ultrastructural level. A monoclonal antibody raised against purified human bone osteosarcoma alkaline phosphatase was used to localize the enzyme in cultures of the osteosarcoma cells. Similar cultures were analyzed for alkaline phosphatase activity using an enzyme cytochemical method with cerium as the capture agent. Alkaline phosphatase was immunolocalized at the light microscopic level in an osteogenic sarcoma and ultrastructurally on the SAOS-2 cell membrane and the enclosing membrane of extracellular vesicular structures close to the cells. In contrast, the TE-85 cells were characterized by the absence of all but a few traces of immunolabeling at the cell surface. Enzyme cytochemical studies revealed strong alkaline phosphatase activity on the outer surface of the SAOS-2 cell membrane. Much lower enzyme activity was observed in the TE-85 cells. The results support biochemical data from previous studies and confirm that SAOS-2 cells have a significantly greater concentration of alkaline phosphatase at the plasma membrane.
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PMID:Presence and activity of alkaline phosphatase in two human osteosarcoma cell lines. 265 62

Two cell lines were established from a human osteosarcoma transplanted into athymic nude mice after the second (O9N2) and fifth passages (HuO9). Both cell lines expressed 1,25(OH)2D3-responsive alkaline phosphatase activity and produced tumors in the dorsum of nude mice that were histologically similar to the original tumor. However, the morphological and growth characteristics of the two cell lines differed. O9N2 cells were large and polygonal, whereas HuO9 cells showed spindle shapes. HuO9 cells had a higher growth rate and saturation density than O9N2 cells. The c-myc oncogene was amplified 4- to 8-fold in HuO9 cells but not in O9N2 cells. Both cell lines had a homozygous internal deletion, lacking the 7.4-kb HindIII fragment in the Rb gene. The results suggest the importance of the c-myc oncogene in the growth and morphological control of human osteosarcoma cells and of the Rb gene in the pathogenesis of the tumor.
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PMID:Two distinct cell lines derived from a human osteosarcoma. 269 14

In this report data are presented which demonstrate that the induction of an osteoblastic phenotype by interleukin-1 beta (IL-1 beta) requires an intermediate step involving signal transduction via the beta 1 family of integrin glycoproteins. Recombinant human IL-1 beta inhibits human osteosarcoma cell proliferation, stimulates integrin expression, and induces alkaline phosphatase activity, a marker of osteoinductive and osteoblastic phenotype. The approximately 10-fold stimulation of expression of the beta 1 integrins occurs rapidly (within 20 to 40 h), whereas the alkaline phosphatase activity is not induced until at least 5 days after the addition of IL-1 beta. To determine whether the early stimulation of integrin expression is required for the subsequent expression of alkaline phosphatase activity, polyclonal as well as monoclonal antibodies directed against the alpha 5 and beta 1 integrin subunits were added to cultures at the same time as IL-1 beta. These antibodies inhibited by 55 to 82% the longer term induction of the osteoblastic differentiation marker, alkaline phosphatase activity, but did not however affect the IL-1 beta-induced stimulation of integrin expression or the inhibition of cell proliferation. In addition, at the concentrations used, there was no effect of the antibodies on cell attachment. These data suggest that the stimulation of integrin expression by IL-1 beta, and the resulting enhanced integrin-extracellular matrix interactions, is a required intermediate event in the IL-1 beta regulation of osteoblastic cell differentiation. The data also suggest that the integrins are capable of signal transduction resulting in altered gene expression, and may also play a crucial role in modulating cytokine-mediated effects on cell differentiation.
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PMID:Signal transduction via the beta 1 integrins is a required intermediate in interleukin-1 beta induction of alkaline phosphatase activity in human osteosarcoma cells. 278 15

Osteosarcoma in the metaphysis to epiphysis of the left femur of a 17-year-old male is reported. The lesion appeared osteolytic with sclerotic foci on roentgenographs, accompanied by an extensive tumor shadow in the surrounding soft tissue. While 60% of the tumor was necrotic, histological examination of the remaining viable tissue revealed that it consisted almost entirely of a sheet of epithelioid cells, separated by thin, fibrovascular septa with an alveolar-like pattern, suggestive of metastatic carcinoma. Only a few areas were characterized by malignant osteoid tissue intermingled with the above cells, showing significant positivity for bone-specific alkaline phosphatase and 5'-nucleotidase, thus permitting a diagnosis of osteosarcoma. Autopsy findings revealed that the metastatic foci were histologically similar to those of the primary tumor. Electron microscopy revealed poor development of cytoplasmic organelles, supporting possible derivation from an osteoblastic cell lineage at an early stage.
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PMID:Osteosarcoma with prominent epithelioid features. 280 Nov 14

The study of bone cancer has been difficult in part due to a lack of appropriate in vitro osteosarcoma model systems. The development of such systems is essential if a clearer understanding of the biology of and mechanisms behind the formation and progression of bone cancers is to be obtained. We report here the development of an in vitro model system which demonstrates important characteristics generally associated with osteosarcoma. The chick periosteal osteogenesis model was infected with the Fujinami Sarcoma Virus (FSV) containing the v-fps oncogene which encodes for a P140gag-fps protein-tyrosine kinase. Under the appropriate conditions FSV infected cultures developed bone and cartilaginous tissues which showed histopathological findings consistent with osteosarcoma. Biochemical data indicating massive increases in alkaline phosphatase activity, protein content, 3H-Thymidine incorporation as well as expression of active P140gag-fps confirm that transformation has occurred in FSV infected cultures. This novel in vitro model system should prove most useful in the study of bone cancer.
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PMID:In vitro transformation of osteoblasts: putative formation of osteosarcoma in vitro. 282 12

Retinoic acid (RA) inhibits the increases in alkaline phosphatase (AP) and hormone-stimulated adenylate cyclase that accompany the growth of ROS 17/2.8 osteosarcoma cells in culture. The RA effects were first detected 2 days after initiation of treatment and were dose dependent, with an EC50 of 100 nM. The reduction in the hormone-responsive adenylate cyclase activity was associated with lower levels of beta-catecholamine receptors, without a change in apparent receptor affinity and with lower levels of the GTP-binding proteins Gs and Gi, visualized by NAD-dependent [32P]ADP ribosylation. The reduction in AP was correlated with a decrease in the steady state level of AP mRNA. RA had no effect on cell proliferation or saturation density. Retinoids thus inhibit the same features that are promoted by glucocorticoids in ROS 17/2.8 cells. These features seem to be subject to coordinate regulation, probably at the pretranslational level.
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PMID:Effects of retinoic acid on alkaline phosphatase messenger ribonucleic acid, catecholamine receptors, and G proteins in ROS 17/2.8 cells. 282 98

A photoreactive derivative of a sulfur-free bovine parathyroid hormone (PTH) analogue, [Nle8,N-epsilon-(4-azido-2-nitrophenyl)Lys13,Nle18,Tyr34]bovine PTH-(1-34)-NH2 (NAP-NlePTH), was purified from the products of the reaction of [Nle8,Nle18,Tyr34]bovine PTH-(1-34)-NH2 (NlePTH) with 4-fluoro-3-nitro-phenylazide and was used to identify binding components of the PTH receptor in clonal rat osteosarcoma cells (ROS 17/2.8). The purified analogue, NAP-NlePTH, is a fully active agonist in three different ROS 17/2.8 cell bioassays: 1) specific binding to saturable PTH receptors; 2) stimulation of cyclic AMP accumulation; and 3) inhibition of cellular alkaline phosphatase activity; this analogue gave dose response curves parallel to and 25-33% as potent as its parent molecule, NlePTH. Radioiodinated NAP-NlePTH (125I-labeled NAP-NlePTH) retained maximal receptor-binding potency. Radioligand saturation studies in intact cells showed that the Kd of PTH receptors for the photoligand was slightly less than that for 125I-labeled NlePTH (2.8 and 0.8 nM, respectively), but that the Bmax was essentially identical for both radioligands (8 fmol/10(5) cells). Photoaffinity labeling of ROS 17/2.8 cells revealed several 125I-labeled macromolecular components by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. One predominant 125I-labeled band, having an apparent Mr of 80,000 daltons (including Mr = 4,347 ligand; hereafter referred to as the Mr = 80,000 protein), was consistently demonstrated in both reducing and nonreducing conditions. Its labeling was completely inhibited by coincubation with NlePTH (10 nM) at 26-fold molar excess to the photoligand, but not by biologically inactive PTH fragments or unrelated hormone. Labeling of several other macromolecular components persisted in the presence of NlePTH (1 microM). Only the labeling of the Mr = 80,000 protein showed saturation kinetics for photoaffinity labeling; the dose of 125I-labeled NAP-NlePTH (0.8 nM) to half-saturate labeling of the Mr = 80,000 protein was close to the Kd (2.8 nM) of specific binding of the photoligand to receptors in intact ROS 17/2.8 cells. Pretreatment of the cells with NlePTH and dexamethasone led to the predicted proportional decrease or increase, respectively, in labeling of the Mr = 80,000 protein. Our data, using a highly purified photoactive derivative of PTH, having carefully defined chemical and biological properties, show a plasma membrane component of Mr = 80,000 in ROS 17/2.8 cells that possesses the affinity, binding capacity, and physiological characteristics of the PTH receptor.
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PMID:Photoaffinity labeling of parathyroid hormone receptors in clonal rat osteosarcoma cells. 283 Dec 8

We characterized the alkaline phosphatase activity of the human osteogenic sarcoma cell line, SAOS-2, and studied the regulation of this enzyme and 3',5'-cyclic adenosine monophosphate levels by 1,25-dihydroxyvitamin D3 and triamcinolone acetonide. We report that the basal alkaline phosphatase activity of SAOS-2 cells was 100-1000 times greater than that of other established human osteogenic sarcoma cell lines. The enzymatic activity was thermolabile, could be inhibited by levamisole and L-homoarginine, but not by L-phenylalanine, and was immunoprecipitable with anti-bone/liver/kidney, but not with anti-placental antibody, confirming that it is the tissue-unspecific or bone/liver/kidney isoenzyme. However, in contrast to other established human osteosarcoma cell lines (TE-85, SAOS-1), in which alkaline phosphatase activity is stimulated several-fold by the steroid hormones 1,25-dihydroxyvitamin D3 and hydrocortisone, the alkaline phosphatase activity of SAOS-2 cells was not affected by 1,25-dihydroxyvitamin D3 treatment despite the presence of classical receptors for this hormone. Furthermore, administration of the potent glucocorticoid analogue, triamcinolone acetonide, induced only a modest increase in activity. The SAOS-2 cell line expressed low basal cAMP levels (28 pmol/10(6) cells) which could be increased 25-40 times by pretreatment with parathyroid hormone. However, unlike other osteoblastic models, in which PTH-induced cAMP stimulation is modulated by 1,25-dihydroxyvitamin D3 and glucocorticoids, neither of these hormones had an effect on the PTH-stimulated cAMP levels in SAOS-2 cells. We conclude that the SAOS-2 cell line is an osteoblastic cell model which expresses high levels of tissue-unspecific alkaline phosphatase activity and exhibits limited responsiveness to two steroid hormones.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of a human osteoblastic osteosarcoma cell line (SAOS-2) with high bone alkaline phosphatase activity. 284 3

Previously we have reported the development of a model in vitro system for the study of osteosarcoma. In this system, when chick periosteal explants are infected with Fujinami sarcoma virus (FSV), osteosarcoma-like tissue is formed. In the present study, a series of histopathologic parameters of neoplastic transformation and osteogenesis were quantitated, at a single cell level, by computer-assisted morphometry. Most significantly, it was found that compared to uninfected (control) cultures, in the FSV-infected (experimental) cultures, the bone to osteoid ratio per unit area was decreased due to a relative decrease in the area of bone and an increase in the area of osteoid. The cellularity of the FSV-infected tissues was significantly increased due to an increase in the number of unlabeled and [3H]thymidine-labeled cells, while the proportion of alkaline phosphatase (AP) positive cells decreased. Double-label immunohistochemistry (with anti-P140gag-fps) and histochemistry for AP activity was performed, to demonstrate production of the oncogene-encoded protein, and osteoblastic differentiation respectively. In an in vitro transformation assay, single cells derived from control, uninfected cultures did not grow, while those derived from FSV-infected cultures formed colonies in semisolid medium. Some of these colonies demonstrated AP staining. Taken together these data show that in this in vitro system (i) neoplastic transformation of osteogenic cells does occur, (ii) changes in osteoid and bone production are related to neoplastic transformation, and (iii) osteosarcoma-like changes can be quantitated at the individual cell level.
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PMID:Neoplastic transformation of osteogenic cells: quantitative morphometric analysis of an in vitro model for osteosarcoma. 284 30

Recently we have developed a model in vitro system for the study of factors regulating the histogenesis of osteosarcoma. In this system, Fujinami sarcoma virus (FSV) induces osteosarcomatous changes such as increased cell proliferation and altered patterns of bone and nonmineralized matrix (osteoid) formation. Such changes can be quantitated at the individual cell level, by computer-assisted morphometry. Here we report on the effects of dexamethasone (DEX) on FSV-induced neoplastic transformation and osteogenesis in chick embryonic periosteum cultures, as reflected by a series of histopathological parameters. Most significantly, it was found that compared to 10(-9) M DEX treated cultures, in 10(-7) M DEX pretreated cultures, the bone/osteoid ratio was increased due to a relative increase in the area of bone and a decrease in the area of osteoid. The number of [3H]thymidine-labeled cells decreased significantly, while the proportion of alkaline phosphatase positive cells increased. Double-label immunohistochemistry (with anti-P140gag-fps) and histochemistry for alkaline phosphatase activity was performed, to demonstrate production of the oncogene-encoded protein, and osteoblastic differentiation, respectively. In an in vitro transformation assay single cells derived from 10(-9) M DEX treated cultures formed a significantly higher number of colonies than those obtained from 10(-7) M DEX pretreated cultures. Taken together, the data indicate that in the chick embryonic periosteum culture system, pretreatment with 10(-7) M DEX inhibits the ability of FSV to induce neoplastic transformation. This effect is probably the result of DEX-induced cell differentiation, prior to infection with FSV.
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PMID:Dexamethasone effects on induction of neoplastic transformation by Fujinami sarcoma virus in an in vitro chick embryo periosteal model for osteosarcoma. 284 66


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